The term "cropped frame" refers to the physical size of the sensor, which is the thing inside the camera that captures the image. Nikon uses the DX designation for cropped frame cameras. The sensor measures 24mmx16mm and is smaller than full frame sensors. This produces a "crop-factor" of 1.5x, which has a similar effect to multiplying the focal length of the lens by 1.5x. So a 50mm lens mounted on a DX camera will produce an photo similar to that of a 75mm lens mounted on a full frame camera. Rent Nikon DX cameras here.

Advantages of DX dslr cameras:

DX cameras and lenses are often smaller and lighter than FX cameras and lenses.

The 1.5x crop factor is a good way to dramatically increase the effective focal length of lenses. A 200mm lens will behave like a 300mm.